PARIS -- Former French Open champion Li Na started fast at Roland Garros to beat a nemesis.
The 2011 titlist raced to a 4-love lead after 20 minutes and defeated Anabel Medina Garrigues 6-3, 6-4 in the first round Monday.
Seeded No. 6, Li came into the match 0-3 on clay against Medina Garrigues but broke serve six times and came forward aggressively, winning 13 of 16 points at the net.
No. 4 Agnieszka Radwanska defeated Shahar Peer 6-1, 6-1 in 57 minutes. Radwanska, last year's Wimbledon runner-up, played for the first time since withdrawing before last week's Brussels tournament with a recurrence of the right shoulder injury that has bothered her the past couple of years.
"I decided to have a week of rest and just practice," she said. "I think it was a good move."
She'll next play American Mallory Burdette, who won in her Roland Garros debut Sunday. Radwanska was asked what she knew about her second-round opponent.
"To be honest, not much. Nothing at all, actually," she said with a smile. "I might Google her."
Nick Kyrgios, at 18 the youngest player in the men's draw, made a successful Grand Slam debut by beating 34-year-old Radek Stepanek 7-6 (4), 7-6 (8), 7-6 (11). Kyrgios won despite breaking serve only once.
"When you're good in juniors, it doesn't mean automatically you're going to be good in the men's tennis," Stepanek said. "He has some talent. He's serving big. He definitely has a chance."
No. 6 Jo-Wilfried Tsonga beat Aljaz Bedene 6-2, 6-2, 6-3. No. 31 Marcel Granollers lost to Feliciano Lopez 7-5, 2-6, 6-4, 4-6, 6-4.
American Varvara Lepchenko, seeded 29th, beat Mirjana Lucic-Baroni 6-1, 6-2. No. 24 Julia Goerges lost to Zuzana Kucova 7-6 (8), 6-0.
Playing in sunny, mild weather on center court, Li had a point for a 5-2 lead in the second set but wavered briefly, and her double-fault on break point made it 4-all. She regrouped to break back, then quickly closed out the victory.
The 31-year-old Li is 22-6 this year and was runner-up to Victoria Azarenka at the Australian Open. She next plays American Bethanie Mattek-Sands, who beat Lourdes Dominguez Lino 6-4, 6-1.
Li is one of six former champions in the women's draw. Maria Sharapova, the 2012 winner, was among those to play Monday.
No. 15 Roberta Vinci won in less than an hour, beating Stephanie Foretz Gacon 6-3, 6-0.
Radwanska won while committing only eight unforced errors. She has two titles this year but is just 2-2 on clay this spring and has never advanced beyond the fourth round at Roland Garros.
Her sister, Urszula, beat 30th-seeded Venus Williams in the final match Sunday, 7-6 (5), 6-7 (4), 6-4